<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .father {
            width: 300px;
            height: 300px;
            background-color: pink;
        }

        /*生成的伪元素默认为行内元素*/
        .father::before {
            content: '老鼠';
            /*display: ;*/
        }

        .father::after {
            content: '大米';
        }
    </style>
</head>
<body>
<div class="father">爱</div>
</body>
</html>